Behaviour
Ivy may exaggerate existing cracks and flaws but is unlikely to damage well-maintained walls. © Derek Ramsey (Ram-Man)
There has been considerable discussion and controversy, about ivy’s effect on trees, buildings and other structures:
- clinging roots are thought to penetrate walls causing physical damage to the structure and allowing ingress of water
- some say it literally strangles trees as the ivy stems become thicker with age
- heavy growth of ivy on buildings and trees is believed to increase the risk of windthrow - damage caused by the resistance of the foliage to high winds
However, these views have been challenged:
- well-maintained brickwork is now thought to be relatively unaffected by ivy and even to benefit from the protection the plant covering offers
- evidence for damage to trees is also disputed
- good growth of ivy on buildings certainly offers shelter for other wildlife
